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JAMES T. McDOUGALIJ, or SAN FRANGISGQ-GALIFORNIA.

I Letters Patent No. 73,021,11atedJanuary 7, 1868.

IMPROVED APPARATUS FOR COLLECTING PRECIOUS METALS.

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TO ALL WHOM IT MAY CONCEBN:

Be it known that I, JAMES T. McDOUGALL, of San Francisco, county of San Francisco, State of California, have invented an Improved Gold-Saving Apparatus; and I do hereby declare the following description and accompanying drawings are suficient to enable any person skilled in the art or science to which it most nearly appcrtains to'make and use my said invention or improvement without further invention or experiment.

The object of my invention is to provide a new and improved method of constructing sluices, so as to bring the gold or silver, or the float gold and silvcr, or float amalgam of the precious metals, into contact with metallic copper, thus saving much that is now lost. Thisis accomplished by constructing a sluice-box in the ordinary manner, and placing within it tubes or bars of copper in rows, and in such a manner as to intercept" the stream and cause it to form a succession of eddies, therebychecking the motion of any precious metal, and bringingit into contact with the surface of the copper; the tubcsstanding either perpendicularly or at an inclination, as may be found most convenient or eflicient.

To more fully explain my invention, reference is had to the accompanying drawings, forming a part of this specification, of which Figure lis aplan of mysluice.

Figure 2 is a. side sectional elevation.

Figure 3 is a view of one of thctubes with its standard.

Similar letters of reference indicate like parts.

A is a sluice-box, formed in the usual manner, with a bottom and two sides of boards. Upon the bottom of this box I place in rows the iron standards constructed with a square base, B, and an upright stem, C, which stem is placed diagonally with the base, as shown in fig. 3. These stems may be made of any suitable form, but I prefer to construct them square, and the sluice-box may be entirely filled with them, or spaces may be left between some of the rows, which will serve as rifles in the box. A tube of copper, D, is fitted to each standard, and rises above the top of it, the open spaces above being fitted with aplug of wood, a, by raising or depressing which the tubes are depressed or raised, as the quantity of water may be more or less. The sides of the sluice are also lined with copper to a certain height, as shown at I) 6, and so attached that the plates may readily be removed. As the current of water passes down the sluice, it is converted into an eddy between each series of the intercepting-standards, the direction of the eddy being downward by the simple device of making a lap on the tube, as shown at c c, fig. 1. When it is desirable to remove the amalgam the tubes may be removed from the standards and others substituted, so that the work need not be stopped to clean up, as in ordinary sluices.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. A sluice containing obstructing-standards, so placed as to convert the current into eddies, substantially as'herein described.

2. The iron standards 13 C, together with the removable copper tubes D, or an equivalent device, constructed and arranged substantially as above specified.

3. The plugs a a for raising and lowering the tubes, substantially as described.

4. The copper plates 6 I), when employed and attached to the sides of the sluice, as and for the purpose herein described.

In witness whereof, I have hereunto set my hand and scale I JAMES T. McDOUGALL. [L. 3.]

Witnesses:

C. W. M. SMITH.

J. L. Booms. 

